For self-assembled nanocrystals in three-dimensional (3D) superlattices, called supracrystals, the crystalline structure of themetal nanocrystals (either single domain or polycrystalline) or nanocrystallinity is likely to induce signi! cant changes in the physical properties. Previous studies demonstrated that spontaneous nanocrystallinity segregation takes place in colloidal solution upon selfassembling of 5 nm dodecanethiol-passivated Au nanocrystals. This segregation allows the exclusive selection of single domain and polycrystalline nanoparticles and consequently producing supracrystals with these building blocks. Here, we investigate the in » uence of nanocrystallinity on di# erent properties of nanocrystals with either single domain or polycrystalline structure. In particular, the in » uence of nanocrystallinity on the localized surface plasmon resonance of individual nanocrystals dispersed in the same dielectric media is reported. Moreover, the frequencies of the radial breathing mode of single domain and polycrystalline nanoparticles are measured. Finally, the orientational ordering of single domain nanocrystals markedly changes the supracrystal elastic moduli compared to supracrystals of polycrystalline nanocrystals.
Source : Modulating the Physical Properties of Isolated and Self-Assembled Nanocrystals by Change in Their Nanocrystallinity. N. Goubet, C.Yan, D. Polli, H.Portalès, I.Arfaoui, G. Cerullo and M. P. Pileni Nano Lett., 2013,13, 504−508.